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- 1. MICROBES are said to be UBIQUITOUS
- 4. • Pathogens microbes that cause disease; 3% of microbes are pathogenic • Nonpathogens microbes that do not cause disease
- 7. • Indigenous microbiota • AKA: Human microbiome • the microbes that live on and in the human body • 10 trillion cells x 10 = 100 trillion microbes • Opportunistic pathogens • AKA: Opportunists • microbes that do not cause disease under ordinary conditions, but have the potential to cause disease should the opportunity present itself
- 8. WHY STUDY MICROBIOLOGY? • Microbes are essential for life • Algae and cyanobacteria – a group of photosynthetic bacteria that produce oxygen • Bioremediation –genetically engineered microbes • Antibiotics – some bacteria and fungi produce antibiotics that are used to treat patient with infectious diseases • Genetic engineering - microbes are essential in this field where a gene or genes from one organism (e.g., from bacterium, a human, an animal, or a plant) is/are inserted into a bacterial or yeast cell • Microbes has been used as “cell models”
- 9. • Decomposers or Saprophytes • these microbes break down dead and decaying organic material into inorganic nutrients in the soil • Decomposition • is the process by which substances are broken down into simpler forms of matter
- 10. • Microbial ecology • The study of the relationships between microbes and the environment
- 11. • Microbes serves as important links in food chains • Plankton – microscopic organisms in the ocean that serve as the starting point of many food chains • Phytoplankton – tiny marine plants and algae • Zooplankton – tiny marine animals
- 12. • Biotechnology • the use of living organisms or their derivatives to make or modify useful products or processes
- 13. • microbes causes 2 categories of diseases
- 14. FIRST MICROORGANISMS ON EARTH Archaea and cyanobacteria
- 15. EARLIEST KNOWN INFECTIOUS DISEASES • Bacterial diseases: TB, syphilis • Parasitic worm infections: schistosomiasis, dracunculiasis (guinea worm infection), tapeworm • Bubonic plague (around 1900 BC) • Smallpox (China, 1122 BC) • Rabies, anthrax, dysentery, smallpox, ergotism, botulism, measles, typhoid fever, typhus fever, diphtheria • Syphilis (Europe, 1493) – AKA: Spanish, German, Polish and Turkish pox • In French – Neapolitan disease • In Italian – French or Spanish disease • In English – French Pox
- 16. PIONEERS IN THE SCIENCE OF MICROBIOLOGY • Anton Van Leeuwenhoek • (1632 – 1723) • Father of Microbiology, Father of Bacteriology, Father of Protozoology • Single-lens microscope or simple microscopes • “animalcules” • ROBERT HOOKE • 1635-1703
- 17. PIONEERS IN THE SCIENCE OF MICROBIOLOGY • Theory of spontaneous generation • AKA: Abiogenesis • accdg to leeuwenhoek in this theory that “Life can arise spontaneously from nonliving material” • Louis Pasteur and John Tyndall • disproved the theory of spontaneous generation and proved that life can only arise from preexisting life (Theory of Biogenesis) • Rudolf Virchow • German scientist who first proposed the theory of biogenesis
- 18. PIONEERS IN THE SCIENCE OF MICROBIOLOGY • Louis Pasteur (1822-1895) • a French chemist who made numerous contributions to the newly emerging field of microbiology • His most significant contributions: • Fermentation • Yeasts convert the glucose in grapes to ethyl alcohol (ethanol) • Acetobacter (a bacteria) that convert glucose to acetic acid (vinegar)
- 19. PASTEUR’S CONTRIBUTION • Theory of spontaneous generation • “aerobes” and “anaerobes” • Pasteurization • a process that kill microbes that were causing wine to spoil • Discovered the infectious agents that cause the silkworm disease • Germ theory of disease • Anthrax (Bacillus anthracis) • Tuberculosis (Mycobacterium tuberculosis) • Hospital practices • Developed vaccines • Vaccines to prevent rabies in dogs
- 20. PIONEERS IN THE SCIENCE OF MICROBIOLOGY • Robert Koch (1843 – 1910) • a German physician, made numerous contributions to the science of microbiology • His most significant contributions: • Germ Theory of disease • Anthrax bacillus (B. anthracis) • he also discovered that this bacteria produces spores, capable of resisting adverse conditions • Koch’s Postulates
- 21. KOCH’S CONTRIBUTION • Methods of fixing, staining, and photographing bacteria • Methods of cultivating bacteria in a solid media • R.J. Petri – invented a flat glass dish (AKA: Petri dish) in which to culture bacteria on solid media • Frau Hesse – who suggested the use of AGAR (a polysaccharide obtained from seaweed) as a solidifying agent • M. tuberculosis and Vibrio cholera • Tuberculin (a protein derived from M. tuberculosis)
- 22. KOCH’S POSTULATES • A particular microbe must be found in all cases of the disease and must not be present in healthy animals or humans. • The microbe must be isolated from the diseased animal or human and grown in pure culture in the laboratory • The same disease must be produced when microbes from the pure culture are inoculated into healthy susceptible laboratory animals • The same microbe must be recovered from the experimentally infected animals and grown again in pure culture
- 23. EXCEPTIONS TO KOCH’S POSTULATES • Obligate intracellular pathogens • AKA: Obligate intracellular parasites • they can survive and multiply only with living host cells • e.g. viruses, rickettsias, chlamydias, M. leprae & Treponema pallidum • Pathogens are species-specific • it infect only one species of animal • Diseases called Synergistic infections or polymicrobial infections • are caused not by one particular microbe but by the combined effects of two or more different microbes • e.g. Acute necrotizing ulcerative gingivitis (AKA: “Trench mouth” and bacterial vaginosis • Certain pathogens become altered when grown in vitro • some becomes less pathogenic, whereas others become non-pathogenic • Thus, they will no longer infect animals after being cultures on artificial media
- 24. CAREERS IN MICROBIOLOGY • Microbiologist • a scientist who studies microbes • Bacteriologist • a scientist who specializes in bacteriology: the study of the structures, functions and activities of bacteria • Phycologists/ Algologists • scientists specializing in the field of phycology/algology who study the various types of algae • Protozoologists • who explore the area of protozoology: the study of protozoa • Mycologists • those who specializes in the study of fungi • Virologists • who study viruses and their effects on living cells of all types • they also study prions and viroids, acellular infectious agents that are even smaller than viruses • Virologists and cell biologists • may become genetic engineers who transfer genetic material (DNA) from one cell type to another
Editor's Notes
- Micro – means a very small- anything so small that it must be viewed with a microscope- an optical instrument used to observe very small objects Microbiology – is the study of microbes; with only rare exceptions, individual microbes can be observed only with the use of various types of microscopes includes the study of certain nonliving entities as well as certain living organisms: MICROBES can be defined as the study of microbes ubiquitous –meaning they are virtually everywhere
- In all likelihood, your mother was your first microbiology instructor. Germs are the microbes that cause disease Your mother worried that you might become infected with these types of microbes
- The two major categories of microbes ACELLULAR microbes – AKA: Infectious particles; include viruses and prions CELLULAR microbes – AKA: Microorganism; include all bacteria, all archaea, all protozoa, some algae and some fungi CELLULAR MICROBES Prokaryotes – are less complex; organisms composed of cells that lack a TRUE nucleus, such as archaea and bacteria Eukaryotes – are more complex; organisms composed of cell that contain a true nucleus, such as algae, fungi and protozoa
- Some non-pathogens are beneficial to us, whereas other have no effect on us all You will learn about both categories: the microbes that help us “microbial allies” and those that harm us “microbial enemies”
- although they are very small, microbes play a significant roles in our lives we have, living on and in our bodies (e.g. on our skin, and in our mouths and intestinal tract It has been estimated that perhaps as many as 500 to 1,000 different species of microbes live on and in us
- The use of the older terms “normal flora” and “indigenous microflora” is discouraged because “flora” refers to plants. Microbes are not plants. Opportunists – although these microbes usually do not cause us any problems, they have the potential to cause infections if they gain access to apart of our anatomy where they do not belong ex: a bacterium called Escherichia coli lives on intestinal tract. This organism does not cause us any harm as long as it remains in our intestinal tract, but can cause disease if it gains access to our urinary bladder, bloodstream, or a wound Other opportunistic pathogens strike when a person becomes run-down, stressed out, or debilitated (weakened) as a result of some disease or condition Thus, opportunistic pathogens can be thought of as microbes awaiting the opportunity to cause disease
- Some microbes produce oxygen by the process known as photosynthesis. Actually, microbes contribute more oxygen to our atmosphere than do plants Bioremediation – some microbes are capable of decomposing industrial wastes (oil spills) Antibiotics – is a substance produced by a microbe that is effective in killing or inhibiting the growth of other microbes; the use of microbes in the antibiotic industry is an example of biotechnology Genetic engineering – because a gene contains the instructions for the production of a gene product (usually a protein), the cell that receives a new gene can now produce whatever product is coded for by that gene Microbiologists have engineered bacteria and yeasts to produce a variety of useful substances, such as insulin, various types of hormones, interferons, and materials used for vaccines
- Saprophyte is an organism that lives on dead or decaying organic matter Saprophytes aid in fertilization by returning inorganic nutrients to the soil They break down dead and dying organic materials (plants and animals) into nitrates, phosphates, and other chemicals necessary for the growth of plants
- many microbes are involved in elemental cycles, such as the carbon, nitrogen, oxygen, sulfur and phosphorus cycles In the nitrogen cycle, certain bacteria convert nitrogen gas in the air to ammonia in the soil; Other soil bacteria then convert the ammonia to nitrites and nitrates; Still other bacteria convert the nitrogen in nitrates to nitrogen gas, to complete the cycle Farmers – as natural fertilizer
- * algae and bacteria serves as food for tiny animals; Then, larger animals eat the smaller creatures and so on
- many microbes are essential in various food and beverage industries, whereas others are used to produce certain enzymes and chemicals
- Microbes cause two categories of diseases: infectious diseases and microbial intoxications An infectious disease results when a pathogen colonizes the body and subsequently causes disease A microbial intoxication results when a person ingests a toxin (poisonous substance) that has been produced by a microbe Anyone pursuing a career in a health care profession must be aware of infectious diseases, the pathogens that cause them, the sources of the pathogens, how this diseases are transmitted, and how to protect yourself and your patients from these diseases Healthcare professionals who are associated with patients and patient care must take precautions to prevent the spread of pathogens harmful microbes may be transferred from health care workers to patients; from pt to pt; from contaminated mechanical devices, instruments and syringes to pt; from contaminated bedding, clothes, dishes, and food to patients; and from patient to health care workers, hospital visitors and other susceptible persons To limit the spread of pathogens, sterile, aseptic, and antiseptic techniques (Chapter 12) are used everywhere in hospitals, nursing homes, operating rooms and laboratories
- * many people believe that syphilis was carried to Europe by Native Americans who were brought to Portugal by Christopher Columbus
- Because he is the first person to see live bacteria and protozoa he is known as Father of……….. But many scholars believe that ROBERT HOOKE, an English physician, was first person to observe and describe microbes, including fossilized protozoan and two species of live microfungi animalcules – various tiny living creatures found in the specimens thru microscope
- But this theory was debated and tested
- while attempting to discover why wine becomes contaminated with undesirable substances, Pasteur discovered what occurs during alcoholic fermentation he also demonstrated that different types of microbes produce different fermentation products………………..
- Pasteur discovered forms of life that could exist in the absence of oxygen. Aerobes (organism that require oxygen); Anaerobes (organism that do not require oxygen) Pasteurization involves heating of wine; this process does NOT kill ALL of the microbes in liquids – just the pathogens Germ Theory of disease – the theory that specific microbes cause specific infectious diseases Pasteur changes in hospital practices to minimize the spread of disease by pathogens Pasteur developed vaccines to prevent chicken cholera, anthrax and swine erysipelas (a skin disease) successfully used the vaccine to treat human rabies (rabies vaccine)
- * Anthrax bacillus – was truly the causative agent of anthrax
- Petri dish: These methods enabled Koch to obtain pure cultures of bacteria. The term pure culture refers to a condition in which only one type of organism is growing on a solid culture medium or in a liquid culture medium in the laboratory Petri dishes containing agar are still used to culture bacteria and fungi in laboratories Tuberculin – that ultimately led to the development of a skin test valuable in diagnosing tuberculosis
- Koch’s postulates is an experimental procedure to prove that a specific microbe is the cause of a specific infectious disease After completing these steps, the microbe is said to have fulfilled Koch’s Postulates and has been proven to be the cause of that particular infectious disease Koch’s Postulates not only helped to prove the germ theory of disease but also gave a tremendous boost to the development of microbiology by stressing laboratory culture and identification of microbes
- Circumstances do exist in which Koch’s Postulates cannot be fulfilled 1st: To fulfill Koch’s Postulates, it is necessary to grow (culture) the pathogen in the laboratory (in vitro) in or on artificial culture media. However, certain pathogens will not grow on artificial media such organisms can be grown in cell cultures (cultures of living human or animal cells of various types), embryonated chicken eggs, or certain animals (laboratory animals) Leprosy bacterium (Mycobacterium leprae) is propagated in armadillos Spirochetes of syphilis (Treponema pallidum) grow well in the testes of rabbits and chimpanzees 2nd : For example, some pathogens that infect humans will infect only humans. Thus, it is not always possible to find a laboratory animal that can be infected with pathogen that causes human disease. Because human volunteers are difficult to obtain and ethical considerations limit their use, the researcher may only be able to observe the changes caused by the pathogen in human cells that can be grown in the laboratory (cell cultures) It is also important to keep in mind that not all diseases are caused by microbes. Many diseases, such as rickets and scurvy, result from dietary deficiencies Some diseases are inherited because of an abnormality in the chromosomes, as in sickle cell anemia. Others, such as diabetes, result from malfunction of a body organ or system. Still others, such as cancer of the lungs and skin, are influenced by environmental factors However, all infectious diseases are caused by microbes, as are all microbial intoxications
- * Genetic engineer- the science of making changes to the genes of a plant or animal to produce a desired result